What does FDD mean?

FDD is one of the full-duplex communication technologies used in mobile communication system, which corresponds to TDD. FDD uses two independent channels to transmit information downward and upward respectively. In order to prevent mutual interference between adjacent transmitters and receivers, there is a guard band between the two channels.

FDD requires two independent working channels. One channel is used to send information from the base station to the end user, and the other channel is used to send information from the end user to the base station.

Extended data

The Ministry of Industry and Information Technology said that according to the applications of relevant enterprises, after a comprehensive review of the financial, technical and operational capabilities of the applicant enterprises in accordance with the Telecommunications Regulations and the Measures for the Administration of Telecommunication Business Licenses,

Issue the business license of "LTE/ Fourth Generation Digital Cellular Mobile Communication Service (FDD-LTE)" to China Telecom and China Unicom to support enterprises to promote the development of 4G convergence and promote information consumption according to their own actual conditions.

On 20 13 12.4, the Ministry of Industry and Information Technology issued the first batch of TD-LTE 4G licenses to China Mobile (Weibo), China Telecom and China Unicom respectively. At present, China's 4G standards include TD-LTE and FDD-LTE. FDD-LTE is the mainstream standard in most countries in Europe and America, while TD-LTE is the dominant standard in China.

Baidu encyclopedia-FDD